Fig. 16. The Scamnum in dislocation of the jaw. After Vidius.
Fig. 17. Counterextension by an axillary loop on the injured side and a perineal band on the other. Extension by a clove hitch above the knee. The surgeon’s hands are seen levering the head of the bone inwards while the assistant props the left side of the body.
[Fig. 15] shows reduction of the humerus. While the extension and counterextension are made, the assistant pulls outwards the head of the humerus by a thong passed under the arm in the axilla.
[Fig. 16] shows reduction of a dislocated jaw. Heliodorus is the only author who describes the use of a machine for this purpose, and it seems rather a superfluous display of force but it may occasionally have been necessary, as from what Hippocrates says it would seem that owing to the dearth of practitioners in some parts it was not uncommon to meet with cases which had remained unreduced for some time.
Of dislocation outwards at the hip ([Fig. 17]) Paulus Ægineta says:
“If the dislocation is outwards, the extension is to be made as above, but the thong at the perineum is to be passed by the opposite parts, the groin at the one side, the clavicle at the other. The surgeon is to propel the limb from without inwards, the lever being fixed in one of the furrows formerly prepared, and an assistant fixing the sound nates, that the body may not yield.”
Hippocrates says that instead of the perineal extension band the upright perineal prop may be used.